1. Field of the Invention
The invention is directed to an automatic control system for controlling the speed of a harvesting assembly. More specifically, the present invention comprises an electronic controller for controlling the speed of a harvesting reel, pickup belt, row crop head gathering belts and/or corn head gathering chains and snapper rolls.
2. Description of the Prior Art
Harvesting machines, such as combines, may be provided with different harvesting assemblies. More specifically, the farmer may use a harvesting platform for small grain and a row crop header for soybeans. Each harvesting assembly is provided with a gathering unit. The harvesting platform may be provided with a reel or belt pick-up. The typical row crop header is provided with rubber gathering belts. A corn head type of row crop header is provided with snapping rolls and gathering chains for gathering the corn stalks to the combine. It is important that these gathering units be driven at a specified ratio of the ground speed of the combine to minimize harvesting losses.
The reel of the harvesting platform is used to draw a section of the crop against the cutter bar of the harvesting platform. After cutting, the reel pushes or lifts the crop into the path of a collecting auger assembly. Reels may either comprise a bat or slat type reel, or a pickup reel having fingers for picking up downed crops. The speed of the reel is a critical variable in controlling harvesting losses. If the reel is rotating too slow, the crop is not pushed against the cutter bar, and the cut crop will fall on the ground as the reel does not push it onto the platform. Alternatively, if the reel is rotating too fast, the crop may be shattered by the impact of the reel or maybe pushed down before it can be cut leaving the uncut grain on the field. Therefore, it is desirable to drive the reel at a speed that is some ratio of the ground speed. Under most conditions, in upright crops, it is desirable to run the reel at 1.25-1.5 of the ground speed of the combine. However, in other crop conditions, different reel speeds may be desirable.
With conventional or modern harvesting platforms, the reel is driven by a hydraulic motor. The operator by controlling the flow of hydraulic fluid to the motor controls the speed of the reel. As this is a manual procedure, the operator must constantly monitor the reel and its impact on the standing grain to insure the reel is being driven correctly. This becomes difficult when the operator must speed up or slow down for varying field conditions because it necessitates continual adjustment of the reel speed. Electronic control system for controlling the various combine operations are illustrated in U.S. Pat. Nos. 4,332,127, 4,337,611, 4,513,562 and 4,527,241. An automatic electronic control system for controlling the reel speed of a harvesting platform is proposed in U.S. Pat. No. 4,430,846. In this patent, an electronic ground speed sensor provides a ground speed signal to electronic circuitry which adjusts an electrohydraulic valve controlling the speed of the reel. Other reel speed control systems for harvesting platforms are disclosed in U.S. Pat. Nos. 4,142,348, 4,188,772, and 4,205,508.
A pickup platform is provided with a pickup belt for gathering in a windrowed crop. The belt is provided with steel or plastic fingers that engage the windrow and gather it into the platform. As with the reel, the pickup belt is driven by a hydraulic motor. It is important that the pickup belt be driven at a correct speed relative to the ground speed of the combine. For example, excessive speeds will result in shattering losses by the fingers contacting the grain. Fast speeds also tend to tear apart the windrow causing uneven feeding of the threshing cylinder. A slow pickup speed, relative to the ground speed of the combine, may result in bunching, increase shatter losses, and uneven feeding. It is desirable that the speed of the pickup belt be adjusted to operate at a speed that makes it appear that the windrow is simply being lifted up as the pickup goes underneath.
On the corn head, the snapping rolls grab the corn stalks and pull them rapidly down between the rolls. As the ear of corn reaches a snapping bar the ear is snapped free from the stalk. The gathering chains guide the corn stalks into the snapping rolls, catch the snapped ears and direct them to the combine. It is important that the snapping rolls and gathering chains be operated at a correct speed relative to the ground speed of the combine. The relative speed of the gathering chains to the snapping rolls is fixed by the head. The snapping rolls must operate to pull the stalks through the rolls before the combine rolls over them. Excessive speed may cause the ears to bounce off the corn head.
The rubber gathering belts on the typical row crop header hold the crop while it is being cut by a knife. Then, after the crop is cut, the gather belts transport the crop to the combine. It is desirable that they be driven at approximately the same speed as the combine to minimize harvesting losses.
Typically, the row crop header and the corn head are driven by a belt coupled to the driven sheave on the feederhouse. The speed of the feederhouse is regulated by a variable sheave assembly. The variable sheaves are provided with hydraulic actuators for controlling the diameter of the variable sheave and thereby the speed of the feederhouse. As such, the speed of the feederhouse relative to the headers is constant, and only by changing the speed of the feederhouse does the speed of the header change.